SP600125-JNK抑制剂对大鼠脑缺血再灌注神经元的保护作用

Neuroprotective effect of SP600125, an inhibitor of JNK on brain ischemia/reperfusion in rats

目的:探讨SP600125-JNK特异性抑制剂对大鼠脑缺血再灌注神经元损伤的保护性作用及其作用机制.方法:雄性SD大鼠108只,体质量290～310g,随机分成假手术组(SH组),缺血再灌注组(IR组),JNK抑制剂SP600125组(SP组),分别于缺血前30min侧脑室注射10mL/LDMSO,10mL/LDMSO及JNK抑制剂SP600125.每组根据再灌注时间分为2,6,12,24,48和72h6个亚组,每亚组6只动物.采用4-VO法建立SD大鼠全脑缺血模型,在预定时间点行灌注、固定、取脑、石蜡包埋切片,光镜下计数CA1区存活细胞,TUNEL法检测CA1区凋亡细胞,免疫组化检测DNA修复蛋白X线修复交叉互补蛋白1(XRCC1)的表达变化.结果:脑缺血再灌注后海马CA1区神经元存活数目SP组高于IR组(P<0.01),凋亡细胞数目低于IR组(P<0.01).SH组XRCC1表达量较强,IR组XRCC1的表达2h即已开始下降,与SH组比较有统计学差异(P<0.01).SP组XRCC1表达量的降低不明显,各时点与IR组比较均有统计学差异(P<0.01).结论:在大鼠全脑缺血再灌注损伤过程中,SP600125-JNK特异性抑制剂对神经元起到了显著的保护性作用,其机制可能为抑制DNA修复蛋白下调的方式维护DNA修复功能,从而减少神经元的凋亡.

AIM： To investigate the neuroprotective effect of SP600125 on cerebral ischemia/reperfusion in rats and its possible mechanism. METHODS： 108 SD rats weighing 290 310 g were randomly divided into sham operation group （SH）, ischemia/reperfusion group（IR） or JNK inhibitor SP600125 group （SP）. The rats were given 10 mL/L DMSO（SH group）, 10 mL/ L DMSO （ IR group ） or SP600125 （ SP group ） by intracerebral ventricular infusion 30 min before the ischemia, respectively. Whole brain ischemia （ 6 min ） was induced by four-vessel occlusion, and the rats were fixed at specified time points after reperfusion for 2, 6, 12, 24, 48 and 72 h. The brains were removed, embedded and sliced up. The number of livingc/apoptotic neurons in hippocampal CA1 region was counted separately by histochemistry and TUNEL, and the activity of XRCC1 was detected by immunohistochemical technique. RESULTS ： In SP group, the living neurons in hippocampal CA1 region were much more than those in IR group （ P 〈 0.01 ）, and the apoptotic neurons were much less than those in IR group（P 〈0.01 ）. The XRCC1 in SH group was markedly expressed, whereas in IR group, the expression decreased（P 〈0.01 vs SH group） , and the levels of XRCC1 in SP group were higher than those in IR group at different time pointas （P 〈 0.01 ）. CONCLUSION： SP600125 protects the neurons from apoptosis and death in rat hippocampal CA1 region during whole brain ischemia/reperfusion injury, maybe via suppressing the reduction of DNA repair protein XRCC1.